Diatomaceous earth pool filters (DE pool filters) are commonly found in most residential pool circulation systems. DE filters require diatomaceous earth be introduced into the inlet skimmer port of the pool when the pool motor is on in order to coat the surface of the filter. Diatomaceous earth is a heavy, dense, fine white powder which, when expelled in water, leaves a white residue around the area where the water is expelled. In addition, diatomaceous earth clings to drainage systems and over time can clog these systems. Recently, many counties in the state of California and in other states have passed ordinances making it illegal to flush diatomaceous earth into street sewer systems. These ordinances often provide fines for each instance such dumping is cited.
A significant number of diatomaceous earth pool filters feature a backflush system. When the backflush valve is open, the backflush system reverses the flow of water through the filter, which dislodges contaminants that have accumulated on the filter. The backflushed water is expelled through a discharge tube typically located at ground level so that the contaminants do not go back in the pool. Unfortunately, diatomaceous earth and contaminants are dispersed into nearby landscaping, drainage systems, and sewer systems. Presently, many pool owners, when backflushing their filters, are likely discharging diatomaceous earth into sewer systems in violation of city ordinances. This situation is even more troublesome for pool service companies that backflush numerous pool filters a day, as most diatomaceous earth dumping ordinances provide fines for each instance of dumping. Thus, there is a need to prevent diatomaceous earth from being discharged into the environment when backflushing DE pool filters.